I understand that enabling "Document Content Searchable" in Search settings enables to search through the content of a document and there isa  Flag : Document Content Searchable(IsBodySearchable) on every document record.

In the reference guide, it is mentioned when the document is completely processed by salesforce, it becomes available for search through its content.

I would like to know how long does it take to process the content of a document. I uploaded a .docx file with the content of only one word "chipmunks". Its been 2hrs now and still the particular document record's  Document Content Searchable(IsBodySearchable) flag is not set to TRUE.

Please let me know if there are any additional constraints to make a document searchable through its content.

Constraints such as File Type, MIME etc.

I also observed in my org that all the document records that has " Document Content Searchable" set to TRUE are made available for public use (IsPublic = TRUE). Please confirm if this is also an constraint.